oxalylglycine and Disease-Models--Animal

Topics: Amino Acids, Dicarboxylic; Animals; Animals, Newborn; Blotting, Western; Bronchopulmonary Dysplasia; Disease Models, Animal; Endotoxins; Female; Hypoxia-Inducible Factor 1; Immunohistochemistry; In Vitro Techniques; Injections, Intralesional; Lung; Peptide PHI; Pregnancy; Pregnancy, Animal; Prenatal Care; Pulmonary Alveoli; Pulmonary Circulation; Random Allocation; Rats; Rats, Sprague-Dawley; Reference Values; Respiratory Function Tests; Tissue Culture Techniques

Mitochondrial dysfunction leads to osteoarthritis (OA) and disc degeneration. Hypoxia inducible factor-1α (HIF-1α) mediated mitophagy has a protective role in several diseases. However, the underlying mechanism of HIF-1α mediated mitophagy in OA remains largely unknown. This current study was performed to determine the effect of HIF-1α mediated mitophagy on OA. Therefore, X-ray and tissue staining including HE staining, safranin O-fast green (S-O) and Alcian Blue were used to assess imageology and histomorphology differences of mouse knee joint. Transcriptional analysis was used to find the possible targets in osteoarthritis. Western blot analysis, RT-qPCR and immunofluorescence staining were used to detect the changes in gene and protein levels in the vitro experiment. The expression of HIF-1α was increased in human and mouse OA cartilage. HIF-1α knockdown by siRNA further impair the hypoxia-induced mitochondrial dysfunction; In contrast, HIF-1α mediated protective role was reinforced by prolylhydroxylase (PHD) inhibitor dimethyloxalylglycine (DMOG). In addition, HIF-1α stabilization could alleviate apoptosis and senescence via mitophagy in chondrocytes under hypoxia condition, which could also ameliorate surgery-induced cartilage degradation in mice OA model. In conclusion, HIF-1α mediated mitophagy could alleviate OA, which may serve as a promising strategy for OA treatment.

Topics: Amino Acids, Dicarboxylic; Animals; Apoptosis; Autophagy; Cartilage, Articular; Cell Hypoxia; Cellular Senescence; Chondrocytes; Cytoprotection; Disease Models, Animal; Extracellular Matrix; Female; Humans; Hypoxia-Inducible Factor 1, alpha Subunit; Male; Meniscus; Mice, Inbred C57BL; Middle Aged; Mitochondria; Mitophagy; Osteoarthritis; Protein Stability; Reactive Oxygen Species

Aspergillus fumigatus is one of the most common fungal infections involved in the pulmonary diseases. Hypoxia-inducible factor-1α (HIF-1α) is important for antifungal immunity. Diabetes is a risk factor of pulmonary A. fumigatus infection and could affect the expression of HIF-1α. The aim of this investigation was to evaluate the role of HIF-1α in pulmonary A. fumigatus infection in diabetes. In murine model, we found diabetic mice had aggravated pulmonary A. fumigatus infection and declined expression of HIF-1α following pulmonary A. fumigatus infection. And these changes could be corrected by dimethyloxalylglycine (DMOG), the agonist of HIF-1α. In cell experiment, after A. fumigatus stimulation, hyperglycemic state was with a decreased HIF-1α expression and increased NLRP3/IL-1β signal pathway. The percentages of Th1 and Treg cells decreased, while percentages of Th2 and Th17 increased in hyperglycemic group. DMOG suppressed A. fumigatus-stimulated NLRP3 and IL-1β expressions in hyperglycemic group and corrected Th and Treg cells differentiation. These regulatory effects of DMOG could be dampened by activating of NLRP3. These data indicated that hyperglycemia suppressed the regulatory effect of HIF-1α in pulmonary A. fumigatus infection, which can affect Th and Treg cells differentiation by regulating the NLRP3/IL-1β signal pathway.

Topics: Amino Acids, Dicarboxylic; Animals; Aspergillus fumigatus; Cell Differentiation; Diabetes Mellitus, Experimental; Disease Models, Animal; Gene Expression Regulation; Host-Pathogen Interactions; Hyperglycemia; Hypoxia-Inducible Factor 1, alpha Subunit; Interleukin-1beta; Male; Mice; Mice, Inbred C57BL; NLR Family, Pyrin Domain-Containing 3 Protein; Pulmonary Aspergillosis; Signal Transduction; T-Lymphocytes, Helper-Inducer; T-Lymphocytes, Regulatory

Mitochondrial disorders arise from defects in nuclear genes encoding enzymes of oxidative metabolism. Mutations of metabolic enzymes in somatic tissues can cause cancers due to oncometabolite accumulation. Paraganglioma and pheochromocytoma are examples, whose etiology and therapy are complicated by the absence of representative cell lines or animal models. These tumors can be driven by loss of the tricarboxylic acid cycle enzyme succinate dehydrogenase. We exploit the relationship between succinate accumulation, hypoxic signaling, egg-laying behavior, and morphology in C. elegans to create genetic and pharmacological models of succinate dehydrogenase loss disorders. With optimization, these models may enable future high-throughput screening efforts.

Topics: Adrenal Gland Neoplasms; Amino Acids, Dicarboxylic; Animals; Animals, Genetically Modified; Caenorhabditis elegans; Caenorhabditis elegans Proteins; Cell Hypoxia; Disease Models, Animal; Drug Screening Assays, Antitumor; High-Throughput Screening Assays; Humans; Mutation; Paraganglioma; Pheochromocytoma; Succinate Dehydrogenase; Succinic Acid

Mesenchymal stem cell (MSC) transplantation therapy has been proposed as a promising approach for the treatment of neurodegenerative disease. Chemical and pharmacological preconditioning before transplantation could optimize the therapeutic properties of transplanted MSCs. In this study, we hypothesized that preconditioning treatment with a prolyl hydroxylase inhibitor, dimethyloxalylglycine (DMOG), will increase MSC efficacy and paracrine effects in an amyloid-β (Aβ)-injected Alzheimer rat model. MSCs were incubated in different concentrations of DMOG for 24 h. Cell viability, migration, and antioxidant capacity was assessed in DMOG-treated and non-treated MSCs before transplantation into Aβ-injected rats. In vitro analysis revealed that DMOG treatment increased cell viability, migration, and expression of CXCR4, CCR2, Nrf2, and HIF-1α in the MSCs. Our in vivo results show that DMOG preconditioning enhances a MSC-mediated rescue of learning and memory function in Aβ-injected rats. Furthermore, we found an increased level of BDNF and total antioxidant capacity in the hippocampus of Aβ-injected rats following transplantation of preconditioned relative to untreated MSCs. Our results suggest that preconditioning MSCs with DMOG before transplantation may enhance the efficacy of stem cell based therapy in neurodegenerative disease.

Topics: Alzheimer Disease; Amino Acids, Dicarboxylic; Amyloid beta-Peptides; Animals; Cell Survival; Disease Models, Animal; Mesenchymal Stem Cell Transplantation; Mesenchymal Stem Cells

Inflammatory bowel disease (IBD) is characterized by epithelial barrier dysfunction with resultant inflammation as the mucosal immune system becomes exposed to luminal antigens. The hydroxylase inhibitor dimethyloxalylglycine (DMOG) reduces symptoms in experimental colitis through the upregulation of genes promoting barrier function and inhibition of epithelial cell apoptosis. The immunosuppressive drug cyclosporine reduces inflammation associated with IBD via suppression of immune cell activation. Given the distinct barrier protective effect of DMOG and the anti-inflammatory properties of cyclosporine, we hypothesized that combining these drugs may provide an enhanced protective effect by targeting both barrier dysfunction and inflammation simultaneously. We used the dextran sulfate sodium model of colitis in C57BL/6 mice to determine the combinatorial efficacy of cyclosporine and DMOG. While cyclosporine and DMOG ameliorated disease progression, in combination they had an additive protective effect that surpassed the level of protection afforded by either drug alone. The ability of DMOG to augment the anti-inflammatory effects of cyclosporine was largely due to preservation of barrier function and at least in part due to zonula occludens-1 regulation. We propose that combining the barrier protective effects of a hydroxylase inhibitor with the anti-inflammatory effects of cyclosporine provides added therapeutic benefit in colitis.

Topics: Amino Acids, Dicarboxylic; Animals; Apoptosis; Colitis; Cyclosporine; Disease Models, Animal; Drug Synergism; Drug Therapy, Combination; Hypoxia; Hypoxia-Inducible Factor 1; Immunosuppressive Agents; Intestinal Mucosa; Mice; Mice, Inbred C57BL; Protective Agents; Up-Regulation

BackgroundNecrotizing enterocolitis (NEC) is a devastating neonatal disease characterized by intestinal necrosis. Hypoxia-inducible factor-1α (HIF-1α) has a critical role in cellular oxygen homeostasis. Here, we hypothesized that prolyl hydroxylase (PHD) inhibition, which stabilizes HIF-1α, protects against NEC by promoting intestinal endothelial cell proliferation and improving intestinal microvascular integrity via vascular endothelial growth factor (VEGF) signaling.MethodsTo assess the role of PHD inhibition in a neonatal mouse NEC model, we administered dimethyloxalylglycine (DMOG) or vehicle to pups before or during the NEC protocol, and determined mortality and incidence of severe intestinal injury. We assessed intestinal VEGF by western blot analysis and quantified endothelial cell and epithelial cell proliferation following immunofluorescence.ResultsDMOG decreased mortality and incidence of severe NEC, increased intestinal VEGF expression, and increased intestinal villus endothelial and epithelial cell proliferation in experimental NEC. Inhibiting VEGFR2 signaling eliminated DMOG's protective effect on intestinal injury severity, survival, and endothelial cell proliferation while sparing DMOG's protective effect on intestinal epithelial cell proliferation.ConclusionDMOG upregulates intestinal VEGF, promotes endothelial cell proliferation, and protects against intestinal injury and mortality in experimental NEC in a VEGFR2 dependent manner. DMOG's protective effect on the neonatal intestinal mucosa may be mediated via VEGFR2 dependent improvement of the intestinal microvasculature.

Topics: Amino Acids, Dicarboxylic; Animals; Animals, Newborn; Cell Proliferation; Disease Models, Animal; Endothelial Cells; Enterocolitis, Necrotizing; Hypoxia-Inducible Factor 1, alpha Subunit; Intestines; Mice; Mice, Inbred C57BL; Microcirculation; Prolyl Hydroxylases; Signal Transduction; Vascular Endothelial Growth Factor A; Vascular Endothelial Growth Factor Receptor-2

The cerebellum undergoes rapid growth during the third trimester and is vulnerable to injury and deficient growth in infants born prematurely. Factors associated with preterm cerebellar hypoplasia include chronic lung disease and postnatal glucocorticoid administration. We modeled chronic hypoxemia and glucocorticoid administration in neonatal mice to study whole cerebellar and cell type-specific effects of dual exposure. Chronic neonatal hypoxia resulted in permanent cerebellar hypoplasia. This was compounded by administration of prednisolone as shown by greater volume loss and Purkinje cell death. In the setting of hypoxia and prednisolone, administration of a small molecule Smoothened-Hedgehog agonist (SAG) preserved cerebellar volume and protected against Purkinje cell death. Such protective effects were observed even when SAG was given as a one-time dose after dual insult. To model complex injury and determine cell type-specific roles for the hypoxia inducible factor (HIF) pathway, we performed conditional knockout of von Hippel Lindau (VHL) to hyperactivate HIF1α in cerebellar granule neuron precursors (CGNP) or Purkinje cells. Surprisingly, HIF activation in either cell type resulted in no cerebellar deficit. However, in mice administered prednisolone, HIF overactivation in CGNPs resulted in significant cerebellar hypoplasia, whereas HIF overactivation in Purkinje cells caused cell death. Together, these findings indicate that HIF primes both cell types for injury via glucocorticoids, and that hypoxia/HIF + postnatal glucocorticoid administration act on distinct cellular pathways to cause cerebellar injury. They further suggest that SAG is neuroprotective in the setting of complex neonatal cerebellar injury.

Topics: Amino Acids, Dicarboxylic; Animals; Animals, Newborn; Anti-Inflammatory Agents; Basic Helix-Loop-Helix Transcription Factors; Calcium-Binding Proteins; Cell Proliferation; Cells, Cultured; Cerebellum; Cyclohexylamines; Developmental Disabilities; Disease Models, Animal; Gene Expression Regulation, Developmental; Glucocorticoids; Hedgehog Proteins; Hypoxia, Brain; Mice; Mice, Inbred C57BL; Mice, Transgenic; Microfilament Proteins; Nerve Tissue Proteins; Nervous System Malformations; Neuroprotective Agents; Prednisolone; Purkinje Cells; Thiophenes; Von Hippel-Lindau Tumor Suppressor Protein; Zinc Finger Protein GLI1

Retinitis pigmentosa (RP) is a group of inherited retinal dystrophies characterized by progressive and irreversible loss of vision due to rod and cone degeneration. Evidence suggests that an inappropriate oxygen level could contribute to its pathogenesis. Rod cell death could increase oxygen concentration, reduce hypoxia-inducible factor 1 (HIF-1α) and contribute to cone cell death. The purposes of this study were: 1) to analyze the temporal profile of HIF-1α, its downstream effectors VEGF, endothelin-1 (ET-1), iNOS, and glucose transporter 1 (GLUT1), and neuroinflammation in retinas of the murine model of rd10 ( retinal degeneration 10) mice with RP; 2) to study oxygen bioavailability in these retinas; and 3) to investigate how stabilizing HIF-1α proteins with dimethyloxaloglycine (DMOG), a prolyl hydroxylase inhibitor, affects retinal degeneration, neuroinflammation, and antioxidant response in rd10 mice. A generalized down-regulation of HIF-1α and its downstream targets was detected in parallel with reactive gliosis, suggesting high oxygen levels during retinal degeneration. At postnatal d 18, DMOG treatment reduced photoreceptor cell death and glial activation. In summary, retinas of rd10 mice seem to be exposed to a hyperoxic environment even at early stages of degeneration. HIF-1α stabilization could have a temporal neuroprotective effect on photoreceptor cell survival, glial activation, and antioxidant response at early stages of RP.-Olivares-González, L., Martínez-Fernández de la Cámara, C., Hervás, D., Millán, J. M., Rodrigo, R. HIF-1α stabilization reduces retinal degeneration in a mouse model of retinitis pigmentosa.

Topics: Amino Acids, Dicarboxylic; Animals; Cell Survival; Disease Models, Animal; Down-Regulation; Endothelin-1; Hypoxia-Inducible Factor 1, alpha Subunit; Mice; Mice, Mutant Strains; Nitric Oxide Synthase Type II; Protein Stability; Retina; Retinitis Pigmentosa; Vascular Endothelial Growth Factor A

Crohn's disease (CD) is a chronic inflammatory disease of the gastrointestinal tract (GIT). Cigarette smoke (CS) exposure and chronic obstructive pulmonary disease (COPD) are risk factors for CD, although the mechanisms involved are poorly understood. We employed a mouse model of CS-induced experimental COPD and clinical studies to examine these mechanisms. Concurrent with the development of pulmonary pathology and impaired gas exchange, CS-exposed mice developed CD-associated pathology in the colon and ileum, including gut mucosal tissue hypoxia, HIF-2 stabilization, inflammation, increased microvasculature, epithelial cell turnover, and decreased intestinal barrier function. Subsequent smoking cessation reduced GIT pathology, particularly in the ileum. Dimethyloxaloylglycine, a pan-prolyl hydroxylase inhibitor, ameliorated CS-induced GIT pathology independently of pulmonary pathology. Prior smoke exposure exacerbated intestinal pathology in 2,4,6-trinitrobenzenesulfonic acid-induced (TNBS-induced) colitis. Circulating vascular endothelial growth factor, a marker of systemic hypoxia, correlated with CS exposure and CD in mice and humans. Increased mucosal vascularisation was evident in ileum biopsies from CD patients who smoke compared with nonsmokers, supporting our preclinical data. We provide strong evidence that chronic CS exposure and, for the first time to our knowledge, associated impaired gas exchange cause systemic and intestinal ischemia, driving angiogenesis and GIT epithelial barrier dysfunction, resulting in increased risk and severity of CD.

Topics: Adult; Aged; Amino Acids, Dicarboxylic; Animals; Biopsy; Cell Hypoxia; Colon; Colonoscopy; Crohn Disease; Disease Models, Animal; Disease Progression; Female; Humans; Ileum; Intestinal Mucosa; Lung; Male; Mice; Mice, Inbred C57BL; Middle Aged; Nicotiana; Oxidative Stress; Prolyl Hydroxylases; Prolyl-Hydroxylase Inhibitors; Pulmonary Disease, Chronic Obstructive; Pulmonary Gas Exchange; Risk Factors; Smoke; Smoking; Smoking Cessation; Time Factors; Trinitrobenzenesulfonic Acid

The pathophysiology of chronic kidney disease (CKD) is driven by alterations in surviving nephrons to sustain renal function with ongoing nephron loss. Oxygen supply-demand mismatch, due to hemodynamic adaptations, with resultant hypoxia, plays an important role in the pathophysiology in early CKD. We sought to investigate the underlying mechanisms of this mismatch. We utilized the subtotal nephrectomy (STN) model of CKD to investigate the alterations in renal oxygenation linked to sodium (Na) transport and mitochondrial function in the surviving nephrons. Oxygen delivery was significantly reduced in STN kidneys because of lower renal blood flow. Fractional oxygen extraction was significantly higher in STN. Tubular Na reabsorption was significantly lower per mole of oxygen consumed in STN. We hypothesized that decreased mitochondrial bioenergetic capacity may account for this and uncovered significant mitochondrial dysfunction in the early STN kidney: higher oxidative metabolism without an attendant increase in ATP levels, elevated superoxide levels, and alterations in mitochondrial morphology. We further investigated the effect of activation of hypoxia-inducible factor-1α (HIF-1α), a master regulator of cellular hypoxia response. We observed significant improvement in renal blood flow, glomerular filtration rate, and tubular Na reabsorption per mole of oxygen consumed with HIF-1α activation. Importantly, HIF-1α activation significantly lowered mitochondrial oxygen consumption and superoxide production and increased mitochondrial volume density. In conclusion, we report significant impairment of renal oxygenation and mitochondrial function at the early stages of CKD and demonstrate the beneficial role of HIF-1α activation on renal function and metabolism.

Topics: Adenosine Triphosphate; Amino Acids, Dicarboxylic; Animals; Cell Hypoxia; Disease Models, Animal; Energy Metabolism; Glomerular Filtration Rate; Hypoxia-Inducible Factor 1, alpha Subunit; Kidney; Male; Mitochondria; Oxygen; Oxygen Consumption; Rats, Wistar; Renal Circulation; Renal Insufficiency, Chronic; Renal Reabsorption; Signal Transduction; Sodium; Superoxides; Time Factors

Blood vessels are important tissue structures that deliver oxygen and nutrition. In tumour tissue, abnormal blood vessels, which are hyperpermeable and immature, are often formed; these tissues also have irregular vascularisation and intravasation. This situation leads to hypoperfusion in tumour tissue along with low oxygen and nutrition depletion; this is also called the tumour microenvironment and is characterised by hypoxia, depleted nutrition, low pH and high interstitial pressure. This environment induces resistance to anticancer drugs, which causes an increase in anticancer drug doses, leading to increased side effects. We hypothesised that normalised tumour blood vessels would improve tumour tissue perfusion, resupply nutrition and re-oxygenate the tumour tissue. Chemotherapy would then be more effective and cause a decrease in anticancer drug doses. Here we report a neovascularisation-inducing drug that improved tumour vascular abnormalities, such as low blood flow, blood leakage and abnormal vessel structure. These results could lead to not only an increased chemo-sensitivity and tissue-drug distribution but also an up-regulated efficiency for cancer chemotherapy. This suggests that tumour blood vessel normalisation therapy accompanied by angiogenesis may be a novel strategy for cancer therapy.

Topics: Amino Acids, Dicarboxylic; Animals; Antineoplastic Agents; Cell Line, Tumor; Disease Models, Animal; Female; Mice, Inbred C57BL; Neoplasms; Neovascularization, Pathologic; Prolyl-Hydroxylase Inhibitors; Tumor Hypoxia; Tumor Microenvironment

Hypoxia inducible factor (HIF)-1 pathway signalling has a protective effect against ischemia/reperfusion injury. The prolyl-hydroxylase inhibitor dimethyloxalylglycine (DMOG) activates the HIF-1 pathway by stabilizing HIF-1α. In a rat model of brain death (BD)-associated donor heart dysfunction we tested the hypothesis that pre-treatment of brain-dead donors with DMOG would result in a better graft heart condition.. BD was induced in anesthetized Lewis rats by inflating a subdurally placed balloon catheter. Controls underwent sham operations. Then, rats were injected with an intravenous dose of DMOG (30 mg/kg) or an equal volume of physiologic saline. After 5 hours of BD or sham operation, hearts were perfused with a cold (4°C) preservation solution (Custodiol; Dr. Franz Köhler Chemie GmbH; Germany), explanted, stored at 4°C in Custodiol, and heterotopically transplanted. Graft function was evaluated 1.5 hours after transplantation.. Compared with control, BD was associated with decreased left ventricular systolic and diastolic function. DMOG treatment after BD improved contractility (end-systolic pressure volume relationship E'max: 3.7 ± 0.6 vs 3.1 ± 0.5 mm Hg/µ1; p < 0.05) and left ventricular stiffness (end-diastolic pressure volume relationship: 0.13 ± 0.03 vs 0.31 ± 0.06 mm Hg/µ1; p < 0.05) 5 hours later compared with the brain-dead group. After heart transplantation, DMOG treatment of brain-dead donors significantly improved the altered systolic function and decreased inflammatory infiltration, cardiomyocyte necrosis, and DNA strand breakage. In addition, compared with the brain-dead group, DMOG treatment moderated the pro-apoptotic changes in the gene and protein expression.. In a rat model of potential brain-dead heart donors, pre-treatment with DMOG resulted in improved early recovery of graft function after transplantation. These results support the hypothesis that activation of the HIF-1 pathway has a protective role against BD-associated cardiac dysfunction.

Topics: Amino Acids, Dicarboxylic; Animals; Brain; Disease Models, Animal; Heart Transplantation; Male; Rats; Rats, Inbred Lew; Reperfusion Injury; Tissue Donors; Ventricular Function, Left

The stromal cell-derived factor-1 (SDF-1):CXCR4 is important in myocardial repair. In this study we tested the hypothesis that early upregulation of cardiomyocyte CXCR4 (CM-CXCR4) at a time of high myocardial SDF-1 expression could be a strategy to engage the SDF-1:CXCR4 axis and improve cardiac repair. The effects of the hypoxia inducible factor (HIF) hydroxylase inhibitor dimethyloxalylglycine (DMOG) on CXCR4 expression was tested on H9c2 cells. In mice a myocardial infarction (MI) was produced in CM-CXCR4 null and wild-type controls. Mice were randomized to receive injection of DMOG (DMOG group) or saline (Saline group) into the border zone after MI. Protein and mRNA expression of CM-CXCR4 were quantified. Echocardiography was used to assess cardiac function. During hypoxia, DMOG treatment increased CXCR4 expression of H9c2 cells by 29 and 42% at 15 and 24 h, respectively. In vivo DMOG treatment increased CM-CXCR4 expression at 15 h post-MI in control mice but not in CM-CXCR4 null mice. DMOG resulted in increased ejection fraction in control mice but not in CM-CXCR4 null mice 21 days after MI. Consistent with greater cardiomyocyte survival with DMOG treatment, we observed a significant increase in cardiac myosin-positive area within the infarct zone after DMOG treatment in control mice, but no increase in CM-CXCR4 null mice. Inhibition of cardiomyocyte death in MI through the stabilization of HIF-1α requires downstream CM-CXCR4 expression. These data suggest that engagement of the SDF-1:CXCR4 axis through the early upregulation of CM-CXCR4 is a strategy for improving cardiac repair after MI.

Topics: Amino Acids, Dicarboxylic; Animals; Apoptosis; Cardiotonic Agents; Cell Hypoxia; Cell Line; Disease Models, Animal; Enzyme Inhibitors; Hypoxia-Inducible Factor 1, alpha Subunit; Hypoxia-Inducible Factor-Proline Dioxygenases; Mice, Inbred C57BL; Mice, Knockout; Myocardial Infarction; Myocardium; Rats; Receptors, CXCR4; Recovery of Function; Signal Transduction; Stem Cells; Stroke Volume; Time Factors; Up-Regulation; Ventricular Function, Left

Traumatic brain injury (TBI) is one of the major cause of morbidity and mortality and it affects more than 1.7 million people in the USA. A couple of regenerative pathways including activation of hypoxia-inducible transcription factor 1 alpha (HIF-1α) are initiated to reduce cellular damage following TBI; however endogenous activation of these pathways is not enough to provide neuroprotection after TBI. Thus we aimed to see whether sustained activation of HIF-1α can provide neuroprotection and neurorepair following TBI. We found that chronic treatment with dimethyloxaloylglycine (DMOG) markedly increases the expression level of HIF-1α and mRNA levels of its downstream proteins such as Vascular endothelial growth factor (VEGF), Phosphoinositide-dependent kinase-1 and 4 (PDK1, PDK4) and Erythropoietin (EPO). Treatment of DMOG activates a major cell survival protein kinase Akt and reduces both cell death and lesion volume following TBI. Moreover, administration of DMOG augments cluster of differentiation 31 (CD31) staining in pericontusional cortex after TBI, which suggests that DMOG stimulates angiogenesis after TBI. Treatment with DMOG also improves both memory and motor functions after TBI. Taken together our results suggest that sustained activation of HIF-1α provides significant neuroprotection following TBI.

Topics: 3-Phosphoinositide-Dependent Protein Kinases; Amino Acids, Dicarboxylic; Angiogenesis Inducing Agents; Animals; Brain Injuries, Traumatic; Cell Death; Disease Models, Animal; Erythropoietin; Hypoxia-Inducible Factor 1, alpha Subunit; Male; Maze Learning; Memory Disorders; Mice, Inbred C57BL; Motor Activity; Neuroprotective Agents; Nootropic Agents; Protein Serine-Threonine Kinases; Pyruvate Dehydrogenase Acetyl-Transferring Kinase; RNA, Messenger; Vascular Endothelial Growth Factor A

Although using differentiated stem cells is the best proposed option for the treatment of Alzheimer disease (AD), an efficient differentiation and cell therapy require enhanced cell survival and homing and decreased apoptosis. It seems that hypoxia preconditioning via Dimethyloxalylglycine (DMOG) may increase the capacity of MSC to induce neural like stem cells (NSCs). Furthermore, it can likely improve the viability of NSCs when transplanted into the brain of AD rats.

Topics: Alzheimer Disease; Amino Acids, Dicarboxylic; Animals; Apoptosis; Cell Differentiation; Cell Hypoxia; Cell Movement; Cell Survival; Disease Models, Animal; Hypoxia-Inducible Factor 1, alpha Subunit; Neural Stem Cells; Rats; Transplantation Conditioning

Patients with a germline mutation in von Hippel-Lindau (VHL) develop renal cell cancers and hypervascular tumors of the brain, adrenal glands, and pancreas as well as erythrocytosis. These phenotypes are driven by aberrant expression of HIF2α, which induces expression of genes involved in cell proliferation, angiogenesis, and red blood cell production. Currently, there are no effective treatments available for VHL disease. Here, using an animal model of VHL, we report a marked improvement of VHL-associated phenotypes following treatment with HIF2α inhibitors. Inactivation of vhl in zebrafish led to constitutive activation of HIF2α orthologs and modeled several aspects of the human disease, including erythrocytosis, pathologic angiogenesis in the brain and retina, and aberrant kidney and liver proliferation. Treatment of vhl(-/-) mutant embryos with HIF2α-specific inhibitors downregulated Hif target gene expression in a dose-dependent manner, improved abnormal hematopoiesis, and substantially suppressed erythrocytosis and angiogenic sprouting. Moreover, pharmacologic inhibition of HIF2α reversed the compromised cardiac contractility of vhl(-/-) embryos and partially rescued early lethality. This study demonstrates that small-molecule targeting of HIF2α improves VHL-related phenotypes in a vertebrate animal model and supports further exploration of this strategy for treating VHL disease.

Topics: 5' Untranslated Regions; Amino Acids, Dicarboxylic; Animals; Basic Helix-Loop-Helix Transcription Factors; Brain; Disease Models, Animal; Drug Evaluation, Preclinical; Embryo, Nonmammalian; Gene Expression Regulation; Humans; Hydrazones; Hypoxia-Inducible Factor 1, alpha Subunit; Kidney; Liver; Myocardial Contraction; Neovascularization, Pathologic; Phenotype; Polycythemia; Retinal Vessels; Sulfones; Tumor Suppressor Proteins; von Hippel-Lindau Disease; Zebrafish; Zebrafish Proteins

Targeting hypoxia-sensitive pathways has recently been proposed as a new therapeutic approach to the treatment of intestinal inflammation. HIF-hydroxylases are enzymes which confer hypoxic-sensitivity upon the hypoxia-inducible factor (HIF), a major regulator of the adaptive response to hypoxia. Previous studies have shown that systemic (intraperitoneal) administration of hydroxylase inhibitors such as dimethyloxalylglycine (DMOG) is profoundly protective in multiple models of colitis, however the therapeutic potential of this approach is limited due to potential side-effects associated with systemic drug exposure and the fact that orally delivered DMOG is ineffective (likely due to drug inactivation by gastric acid). In order to overcome these issues, we formulated DMOG in a liquid emulsion drug delivery system which, when coated with specific polymer coatings, permits oral delivery of a reduced dose which is released locally throughout the colon. This colon-targeted DMOG formulation demonstrated increased relative colonic bioactivity with reduced systemic exposure and provided a similar degree of protection to systemic (intraperitoneal) administration at a 40-fold lower dose in DSS-induced colitis. In summary, targeted delivery of DMOG to the colon provides local protection resulting in enhanced efficacy with reduced systemic exposure in the treatment of colitis. This novel approach to targeting hydroxylase inhibitors to specific diseased regions of the GI tract may improve it's potential as a new therapeutic in inflammatory bowel diseases such as ulcerative colitis.

Topics: Administration, Oral; Amino Acids, Dicarboxylic; Animals; Colitis; Colon; Dextran Sulfate; Disease Models, Animal; Drug Delivery Systems; Female; HeLa Cells; Humans; Luciferases, Firefly; Mice; Mice, Transgenic; Mixed Function Oxygenases; NF-kappa B; Treatment Outcome

Although epilepsy is a common neurological disorder, its mechanism(s) are still not completely understood. Hypoxia can lead to neuronal cell death and angiogenesis, and the same mechanisms were also found in epilepsy. Hypoxia-inducible factor-1α (HIF-1α) is an important transcription protein that regulates gene expression in the brain and other tissues in response to decreases in oxygen availability. However, little is known regarding the expression of HIF-1α in the epileptic brain and whether HIF-1α interventions affect the epileptic process. The aims of this study are to investigate the expression profile of HIF-1α in rat models and to explore the role of HIF-1α in epilepsy. We performed Western blots and immunofluorescence in a lithium-pilocarpine rat epilepsy model. To determine the role of HIF-1α in epilepsy, we used the HIF-1α agonist DMOG and inhibitor KC7F2 to detect changes in the animal behavior in pentylenetetrazole (PTZ) and lithium-pilocarpine epilepsy models. The expression of HIF-1α was significantly increased after pilocarpine-induced status epilepticus. DMOG significantly prolonged the latent period in the PTZ kindling model and decreased the rate of spontaneous recurrent seizures during the chronic stage in the lithium-pilocarpine model. Conversely, the inhibitor KC7F2 produced an opposite behavioral change. Interestingly, both KC7F2 and DMOG had no effect on the acute stage of pilocarpine model and PTZ convulsive model. Our study suggests that upregulated HIF-1α may be involved in the process of epileptogenesis but not in the acute stage of epilepsy. The modulation of HIF-1α may offer a novel therapeutic target in epilepsy.

Topics: Acute Disease; Amino Acids, Dicarboxylic; Animals; Brain; Central Nervous System Agents; Chronic Disease; Disease Models, Animal; Disulfides; Epilepsy; Hypoxia-Inducible Factor 1, alpha Subunit; Lithium Compounds; Male; Pentylenetetrazole; Pilocarpine; Random Allocation; Rats, Sprague-Dawley; Seizures; Status Epilepticus; Sulfonamides

The revascularization therapy of pulmonary embolism is associated with ischemia-reperfusion (IR) injury. However, the effect of IR injury on pulmonary arterial endothelial function has not been elucidated. Male Sprague-Dawley rats were divided into a control, an IR and an IR plus hypoxia-inducible factor 1 alpha (HIF-1α) stabilizer DMOG group. We found that the acetylcholine (ACh)-induced relaxation was dramatically reduced in pulmonary arteries from IR-injured rats compared with controls (P < 0.01). Interestingly, pre-treatment with the DMOG significantly improved ACh-stimulated pulmonary arterial dilatation (P < 0.01). The protein expression of HIF-1α in pulmonary artery was significantly down-regulated by IR injury (P < 0.01). Moreover, DMOG remarkably reversed IR-induced down-regulation of HIF-1α (P < 0.01). There was no difference in ACh-stimulated relaxation of endothelium-denuded or L-NMMA-treated pulmonary arteries among the three groups. The bioavailability of nitric oxide (NO) and the phosphorylation level of inducible NO synthase (iNOS) in pulmonary artery were significantly decreased by IR injury (both P < 0.01), which were reversed by DMOG (P < 0.05 or P < 0.01). In addition, the levels of superoxide in pulmonary artery were not affected by the IR injury as well as IR injury plus administration with DMOG. The present study demonstrated that HIF-1α contributes to pulmonary vascular dysfunction in lung IR injury.

Topics: Amino Acids, Dicarboxylic; Animals; Blotting, Western; Disease Models, Animal; Endothelium, Vascular; Hypertension, Pulmonary; Hypoxia-Inducible Factor 1, alpha Subunit; Male; Pulmonary Artery; Pulmonary Embolism; Rats; Rats, Sprague-Dawley; Reperfusion Injury

To study the effect of systemic hypoxia-inducible factor prolyl hydroxylase inhibition (HIF PHDi) in the rat 50/10 oxygen-induced retinopathy (OIR) model.. Oxygen-induced retinopathy was created with the rat 50/10 OIR model. OIR animals received intraperitoneal injections of dimethyloxalylglycine (DMOG, 200 μg/g), an antagonist of α-ketoglutarate cofactor and inhibitor for HIF PHD, on postnatal day (P)3, P5, and P7. Control animals received intraperitoneal injections of PBS. On P14 and P21, animals were humanely killed and the effect on vascular obliteration, tortuosity, and neovascularization quantified. To analyze HIF and erythropoietin, rats at P5 were injected with DMOG (200 μg/g). Western blot or ELISA measured the levels of HIF-1 and Epo protein. Epo mRNA was measured by quantitative PCR.. Alternating hyperoxia and hypoxia in untreated rats led to peripheral vascular obliteration on day P14 and P21. Rats that were treated with systemic DMOG by intraperitoneal injections had 3 times less ischemia and greater peripheral vascularity (P = 0.001) than control animals treated with PBS injections. Neovascularization similarly decreased by a factor of 3 (P = 0.0002). Intraperitoneal DMOG administration increased the levels of HIF and Epo in the liver and brain. Serum Epo also increased 6-fold (P = 0.0016). Systemic DMOG had no adverse effect on growth of rats treated with oxygen.. One of the many controversies in the study of retinopathy of prematurity is whether hyperoxia or alternating hyperoxia and hypoxia creates the disease phenotype in humans. We have previously demonstrated that PHDi prevents OIR in mice exposed to 5 days of sustained 75% oxygen followed by 5 days of 21% oxygen. The 50/10 rat experiments demonstrate that PHDi is also effective in a 24-hour alternating hyperoxia-hypoxia model. The rat OIR model further validates the therapeutic value of HIF PHDi to prevent retinopathy of prematurity because it reduces oxygen-induced vascular obliteration and retinovascular growth attenuation in prolonged and/or alternating hyperoxia.

Topics: Amino Acids, Dicarboxylic; Animals; Animals, Newborn; Blotting, Western; Disease Models, Animal; Enzyme-Linked Immunosorbent Assay; Erythropoietin; Hyperoxia; Hypoxia-Inducible Factor 1; Injections, Intraperitoneal; Neovascularization, Pathologic; Oxygen; Procollagen-Proline Dioxygenase; Rats; Retinal Diseases; Retinal Vessels

Storage protocols of vascular grafts need further improvement against ischemia-reperfusion (IR) injury. Hypoxia elicits a variety of complex cellular responses by altering the activity of many signaling pathways, such as the oxygen-dependent prolyl-hyroxylase domain-containing enzyme (PHD). Reduction of PHD activity during hypoxia leads to stabilization and accumulation of hypoxia inducible factor (HIF) 1α. We examined the effects of PHD inhibiton by dimethyloxalylglycine on the vasomotor responses of isolated rat aorta and aortic vascular smooth muscle cells (VSMCs) in a model of cold ischemia/warm reperfusion. Aortic segments underwent 24 hours of cold ischemic preservation in saline or DMOG (dimethyloxalylglycine)-supplemented saline solution. We investigated endothelium-dependent and -independent vasorelaxations. To simulate IR injury, hypochlorite (NaOCl) was added during warm reperfusion. VSMCs were incubated in NaCl or DMOG solution at 4°C for 24 hours after the medium was changed for a supplied standard medium at 37°C for 6 hours. Apoptosis was assessed using the TUNEL method. Gene expression analysis was performed using quantitative real-time polymerase chain reaction. Cold ischemic preservation and NaOCl induced severe endothelial dysfunction, which was significantly improved by DMOG supplementation (maximal relaxation of aortic segments to acetylcholine: control 95% ± 1% versus NaOCl 44% ± 4% versus DMOG 68% ± 5%). Number of TUNEL-positive cell nuclei was significantly higher in the NaOCl group, and DMOG treatment significantly decreased apoptosis. Inducible heme-oxygenase 1 mRNA expressions were significantly higher in the DMOG group. Pharmacological modulation of oxygen sensing system by DMOG in an in vitro model of vascular IR effectively preserved endothelial function. Inhibition of PHDs could therefore be a new therapeutic avenue for protecting endothelium and vascular muscle cells against IR injury.

Topics: Amino Acids, Dicarboxylic; Animals; Aorta; Apoptosis; Cell Culture Techniques; Disease Models, Animal; Endothelium, Vascular; Enzyme Inhibitors; Heme Oxygenase-1; Hypoxia-Inducible Factor 1, alpha Subunit; In Situ Nick-End Labeling; Isometric Contraction; Male; Muscle, Smooth, Vascular; Procollagen-Proline Dioxygenase; Rats; Rats, Sprague-Dawley; Reperfusion Injury; RNA, Messenger; Vasodilation

Local skin flaps often present with flap necrosis caused by critical disruption of the blood supply. Although animal studies demonstrate enhanced angiogenesis in ischemic tissue, no strategy for clinical application of this phenomenon has yet been defined. Hypoxia-inducible factor 1 (HIF-1) plays a pivotal role in ischemic vascular responses, and its expression is induced by the prolyl hydroxylase inhibitor dimethyloxalylglycine (DMOG). We assessed whether preoperative stabilization of HIF-1 by systemic introduction of DMOG improves skin flap survival.. Mice with ischemic skin flaps on the dorsum were treated intraperitoneally with DMOG 48 hr prior to surgery. The surviving area with neovascularization of the ischemic flaps was significantly greater in the DMOG-treated mice. Significantly fewer apoptotic cells were present in the ischemic flaps of DMOG-treated mice. Interestingly, marked increases in circulating endothelial progenitor cells (EPCs) and bone marrow proliferative progenitor cells were observed within 48 hr after DMOG treatment. Furthermore, heterozygous HIF-1α-deficient mice exhibited smaller surviving flap areas, fewer circulating EPCs, and larger numbers of apoptotic cells than did wild-type mice, while DMOG pretreatment of the mutant mice completely restored these parameters. Finally, reconstitution of wild-type mice with the heterozygous deficient bone marrow cells significantly decreased skin flap survival.. We demonstrated that transient activation of the HIF signaling pathway by a single systemic DMOG treatment upregulates not only anti-apoptotic pathways but also enhances neovascularization with concomitant increase in the numbers of bone marrow-derived progenitor cells.

Topics: Amino Acids, Dicarboxylic; Animals; Apoptosis; Bone Marrow Cells; Bone Marrow Transplantation; Disease Models, Animal; Haploinsufficiency; Hypoxia-Inducible Factor 1, alpha Subunit; Injections, Intraperitoneal; Male; Mice; Mice, Inbred BALB C; Mice, Inbred C57BL; Necrosis; Neovascularization, Physiologic; Procollagen-Proline Dioxygenase; Protective Agents; Skin; Tissue Survival

The goal of this study was to evaluate in vitro and in vivo the effects of up-regulation of the proangiogenic hypoxia inducible factor (HIF)-1α induced by dimethyloxalylglycine on endothelial cell cultures and on skin flap survival.. Human umbilical vein endothelial cell cultures were exposed to hypoxic conditions, to dimethyloxalylglycine, and to cobalt chloride for up to 24 hours. Expression of HIF-1α and vascular endothelial growth factor (VEGF) in cell culture media was analyzed. In vivo, 20 male Wistar rats were assigned randomly to either the treatment group (dimethyloxalylglycine intraperitoneal injection, n = 10) or the control group (saline intraperitoneal injection, n = 10). A dorsal skin flap was raised in all animals and sutured back into place. Flap survival was evaluated on postoperative day 7 by laser Doppler and digital planimetry.. In vitro treatment of human umbilical vein endothelial cells during a 24-hour period showed a significant elevation of VEGF expression with dimethyloxalylglycine exposure (92 ± 35 pg/mg total cellular protein) or hypoxia exposure (88 ± 21 pg/mg total cellular protein) compared with controls (23 ± 10 pg/mg total cellular protein) (p < 0.05 for both). In vivo experiments showed a significant decrease of flap necrosis in the treatment group animals versus controls (35.95 ± 5.03 percent versus 44.42 ± 5.18 percent, p < 0.05). The laser Doppler evaluation revealed significantly increased blood flow in the proximal two-thirds of the flap in the treatment group compared with the control group (p < 0.05).. Dimethyloxalylglycine treatment significantly increases VEGF and HIF-1α expression in endothelial cell cultures and enhances skin flap survival in vivo in a rat model.

Topics: Amino Acids, Dicarboxylic; Animals; Cells, Cultured; Disease Models, Animal; Endothelial Cells; Endothelium, Vascular; Enzyme-Linked Immunosorbent Assay; Follow-Up Studies; Graft Survival; Humans; Hypoxia-Inducible Factor 1, alpha Subunit; Laser-Doppler Flowmetry; Male; Rats; Rats, Wistar; Skin Transplantation; Surgical Flaps; Umbilical Veins

Stem cells protect the heart from ischemic damage in part by the release of cytoprotective growth factors, particularly vascular endothelial growth factor (VEGF). Production of VEGF is regulated in part by levels of the transcription factor hypoxia inducible factor 1-α (HIF-1α). Dimethyloxalylglycine (DMOG) prevents the deactivation of HIF-1α and increases VEGF production. However, the effects of systemic DMOG treatment on myocardial tolerance for ischemia are unknown. We hypothesized that systemic pretreatment with DMOG would improve myocardial ischemic tolerance.. To study this hypothesis, adult male rats were randomly given an intraperitoneal injection of DMOG (40 mg/kg in 1 mL saline, n = 5) or saline (1 mL, n = 6) 24 h before cardiectomy and isolated heart perfusion. All hearts were subjected to 15 min equilibration, 25 min ischemia and 40 min reperfusion. Myocardial function was continuously monitored. Following reperfusion, myocardial homogenates were analyzed for HIF-1α and VEGF production.. We observed that hearts in the DMOG group exhibited greater recovery of left ventricular developed pressure LVDP, +dP/dt and -dP/dt. Myocardial HIF-1α and VEGF levels were increased by DMOG therapy.. In conclusion, systemic pretreatment with DMOG augments post-ischemic myocardial functional recovery through increased HIF-1α levels and greater VEGF production.

Topics: Amino Acids, Dicarboxylic; Animals; Disease Models, Animal; Enzyme Inhibitors; Hypoxia-Inducible Factor 1; Male; Myocardial Reperfusion Injury; Perfusion; Rats; Rats, Sprague-Dawley; Recovery of Function; Vascular Endothelial Growth Factor A

This study investigates whether deoxy-2-[18F]fluoro-d-glucose (FDG) micro-positron emission tomography (μPET)/computed tomography (CT) can serve as a tool for monitoring of the commonly used dextran sodium sulfate (DSS)-induced murine model of inflammatory bowel disease (IBD).. DSS-colitis was induced in Sv129 mice. In a first experiment, four animals were serially scanned with CT and FDG-μPET on days 0, 3, 7, 11, and 14. The ratio of the mean voxel count of the PET images in the colon and the brain was compared with the histological inflammation score and the colonic myeloperoxidase levels. A second experiment was performed to investigate whether FDG-μPET was able to detect differences in inflammation between two DSS-treated groups, one receiving placebo (n = 4) and one receiving dimethyloxalylglycine (DMOG) (n = 4), a compound that protects against DSS-induced colitis.. The progression of the colonic/brain FDG-signal ratio (over days 0-14) agreed with the predicted histological inflammation score, obtained from a parallel DSS-experiment. Moreover, the quantification of normalized colonic FDG-activity at the final timepoint (day 14) showed an excellent correlation with both the MPO levels (Spearman's rho = 1) and the histological inflammation score (Spearman's rho = 0.949) of the scanned mice. The protective action of DMOG in DSS colitis was clearly demonstrated with FDG-μPET/CT (normalized colonic FDG-activity DMOG versus placebo: P < 0.05).. FDG-μPET-CT is a feasible and reliable noninvasive method to monitor murine DSS-induced colitis. The implementation of this technique in this widely used IBD model opens a new window for pathophysiological research and high-throughput screening of potential therapeutic compounds in preclinical IBD research.

Topics: Amino Acids, Dicarboxylic; Animals; Colitis; Dextran Sulfate; Disease Models, Animal; Female; Image Processing, Computer-Assisted; Inflammation; Mice; Mice, Inbred C57BL; Mice, Knockout; Positron-Emission Tomography; Tomography, X-Ray Computed

Chronic hypoxia in the kidney has been suggested as a final common pathway to end-stage renal disease. Hypoxia-inducible factor (HIF) is a transcription factor that regulates cellular hypoxic responses, and it is a promising target with therapeutic potential in various kidney disease models. In this study, we investigated whether HIF activation could attenuate renal injury in the rat remnant kidney model.. Two weeks after a subtotal nephrectomy, rats received a continuous infusion of dimethyloxalylglycine (DMOG) for 4 weeks to activate HIF.. The DMOG infusion halted the progression of proteinuria. A histological evaluation revealed that the glomerulosclerosis and tubulointerstitial injury were significantly decreased by DMOG treatment. DMOG increased renal HIF-1alpha protein. The expression of glucose transporter-1 (GLUT-1) and prolyl hydroxylase 3 (PHD3) and the immunostaining of vascular endothelial growth factor (VEGF) were increased by DMOG. DMOG-treated rats showed less podocyte injury manifested by decreased immunostaining of desmin and the restoration of podoplanin staining. Furthermore, plasma malondialdehyde (MDA), a marker of oxidative stress, showed a tendency to decrease, and the renal expression of catalase, an antioxidant, was significantly increased by DMOG. The DMOG treatment decreased macrophage infiltration and reduced fibrosis, as manifested by decreased type IV collagen and osteopontin expression.. Activation of HIF by DMOG halted the progression of proteinuria and attenuated structural damage by preventing podocyte injury in the remnant kidney model. This renoprotection was accompanied by a reduction of oxidative stress, inflammation and fibrosis.

Topics: Amino Acids, Dicarboxylic; Animals; Chronic Disease; Disease Models, Animal; Disease Progression; Glucose Transporter Type 1; Hypoxia-Inducible Factor 1; Kidney; Kidney Diseases; Male; Nephrectomy; Oxidative Stress; Rats; Rats, Sprague-Dawley; Vascular Endothelial Growth Factor A

Hypoxia-inducible factor-1alpha (HIF-1alpha) has been considered as a regulator of both prosurvival and prodeath pathways in the nervous system. The present study was designed to elucidate the role of HIF-1alpha in neonatal hypoxic-ischemic (HI) brain injury. Rice-Vannucci model of neonatal hypoxic-ischemic brain injury was used in seven-day-old rats, by subjecting unilateral carotid artery ligation followed by 2 h of hypoxia (8% O2 at 37 degrees C). HIF-1alpha activity was inhibited by 2-methoxyestradiol (2ME2) and enhanced by dimethyloxalylglycine (DMOG). Results showed that 2ME2 exhibited dose-dependent neuroprotection by decreasing infarct volume and reducing brain edema at 48 h post HI. The neuroprotection was lost when 2ME2 was administered 3 h post HI. HIF-1alpha upregulation by DMOG increased the permeability of the BBB and brain edema compared with HI group. 2ME2 attenuated the increase in HIF-1alpha and VEGF 24 h after HI. 2ME2 also had a long-term effect of protecting against the loss of brain tissue. The study showed that the early inhibition of HIF-1alpha acutely after injury provided neuroprotection after neonatal hypoxia-ischemia which was associated with preservation of BBB integrity, attenuation of brain edema, and neuronal death.

Topics: 2-Methoxyestradiol; Amino Acids, Dicarboxylic; Animals; Animals, Newborn; Blood-Brain Barrier; Brain; Brain Edema; Brain Infarction; Cytoprotection; Disease Models, Animal; Dose-Response Relationship, Drug; Enzyme Inhibitors; Estradiol; Female; Hypoxia-Inducible Factor 1, alpha Subunit; Hypoxia-Ischemia, Brain; Neuroprotective Agents; Rats; Tubulin Modulators; Vascular Endothelial Growth Factor A

Oxygen-induced retinopathy (OIR) in the mouse, like the analogous human disease retinopathy of prematurity, is an ischemic retinopathy dependent on oxygen-induced vascular obliteration. We tested the hypothesis that chemically overriding the oxygen-induced downregulation of hypoxia-inducible factor (HIF) activity would prevent vascular obliteration and subsequent pathologic neovascularization in the OIR model. Because the degradation of HIF-1alpha is regulated by prolyl hydroxylases, we examined the effect of systemic administration of a prolyl hydroxylase inhibitor, dimethyloxalylglycine, in the OIR model. Our results determine that stabilizing HIF activity in the early phase of OIR prevents the oxygen-induced central vessel loss and subsequent vascular tortuosity and tufting that is characteristic of OIR. Overall, these findings imply that simulating hypoxia chemically by stabilizing HIF activity during the causative ischemia phase (hyperoxia) of retinopathy of prematurity may be of therapeutic value in preventing progression to the proliferative stage of the disease.

Topics: Aerobiosis; Amino Acids, Dicarboxylic; Animals; Basic Helix-Loop-Helix Transcription Factors; Disease Models, Animal; Enzyme Inhibitors; Erythropoietin; Humans; Hypoxia-Inducible Factor 1, alpha Subunit; Infant, Newborn; Kidney; Liver; Mice; Oxygen; Procollagen-Proline Dioxygenase; Retina; Retinopathy of Prematurity; Vascular Endothelial Growth Factor A

Relative hypoxia is essential in wound healing since it normally plays a pivotal role in regulation of all the critical processes involved in tissue repair. Hypoxia-inducible factor (HIF) 1alpha is the critical transcription factor that regulates adaptive responses to hypoxia. HIF-1alpha stability and function is regulated by oxygen-dependent soluble hydroxylases targeting critical proline and asparaginyl residues. Here we show that hyperglycemia complexly affects both HIF-1alpha stability and activation, resulting in suppression of expression of HIF-1 target genes essential for wound healing both in vitro and in vivo. However, by blocking HIF-1alpha hydroxylation through chemical inhibition, it is possible to reverse this negative effect of hyperglycemia and to improve the wound healing process (i.e., granulation, vascularization, epidermal regeneration, and recruitment of endothelial precursors). Local adenovirus-mediated transfer of two stable HIF constructs demonstrated that stabilization of HIF-1alpha is necessary and sufficient for promoting wound healing in a diabetic environment. Our findings outline the necessity to develop specific hydroxylase inhibitors as therapeutic agents for chronic diabetes wounds. In conclusion, we demonstrate that impaired regulation of HIF-1alpha is essential for the development of diabetic wounds, and we provide evidence that stabilization of HIF-1alpha is critical to reverse the pathological process.

Topics: 3T3 Cells; Amino Acids, Dicarboxylic; Animals; Cell Line, Tumor; Chronic Disease; Dermis; Diabetic Foot; Disease Models, Animal; Enzyme Inhibitors; Fibroblasts; Gene Expression; Humans; Hyperglycemia; Hypoxia; Hypoxia-Inducible Factor 1, alpha Subunit; Kidney Neoplasms; Mice; Mice, Inbred C57BL; Mice, Mutant Strains; Mixed Function Oxygenases; Wound Healing

Prolyl and asparaginyl hydroxylases are key oxygen-sensing enzymes that confer hypoxic sensitivity to transcriptional regulatory pathways including the hypoxia inducible factor 1 (HIF-1) and nuclear factor-kappaB (NF-kappaB). Knockout of either HIF-1 or (IKKbeta-dependent) NF-kappaB pathways in intestinal epithelial cells promotes inflammatory disease in murine models of colitis. Both HIF-1 and NF-kappaB pathways are repressed by the action of hydroxylases through the hydroxylation of key regulatory molecules.. In this study we have investigated the effects of the hydroxylase inhibitor dimethyloxalylglycine (DMOG) on Caco-2 intestinal epithelial cells in vitro and in a dextran sodium sulfate-induced model of murine colitis.. DMOG induces both HIF-1 and NF-kappaB activity in cultured intestinal epithelial cells, and is profoundly protective in dextran-sodium sulfate colitis in a manner that is at least in part reflected by the development of an anti-apoptotic phenotype in intestinal epithelial cells, which we propose reduces epithelial barrier dysfunction.. These data show that hydroxylase inhibitors such as DMOG represent a new strategy for the treatment of inflammatory bowel disease.

Topics: Amino Acids, Dicarboxylic; Animals; Caco-2 Cells; Cell Culture Techniques; Colitis; Disease Models, Animal; Enzyme Inhibitors; Female; Humans; Hypoxia-Inducible Factor 1, alpha Subunit; Mice; Mice, Inbred C57BL; Mixed Function Oxygenases; NF-kappa B

Hypoxia-inducible factor (HIF) modulates transcriptional control of several genes involved in vascular growth and cellular metabolism. HIF activity can be enhanced by suppression of prolyl and asparaginyl hydroxylase activity by dimethyloxalylglycine (DMOG). We have compared the effects of DMOG treatment and femoral artery ligation individually or in combination on HIF-1alpha protein level, HIF-dependent gene expression and capillary-to-fibre ratio (C: F) in extensor digitorum longus and tibialis anterior muscles of mice. Immunohistochemical examination revealed that HIF-1alpha is present in non-ischaemic mouse skeletal muscles, but its amount increased profoundly in response to the combination of DMOG treatment and ischaemia. Combined treatment resulted in 39% increase in C: F in ischaemic muscles (P < 0.0001 versus controls) whereas individual treatments produced little effect under our conditions. Combined treatment led to a significant increase in endogenous HIF-1alpha protein (6.14 +/- 1.1 versus 1.17 +/- 0.2 in controls; P < 0.05) that was not apparent in mice treated with DMOG or femoral artery ligation alone. Ischaemia increased vascular endothelial growth factor (VEGF) protein production by 2.5-fold (P < 0.05 versus controls), irrespective of DMOG treatment. However, production of the VEGF receptor Flk-1 was more enhanced in ischaemic + DMOG-treated muscles (P < 0.001 and P < 0.05 compared with controls and untreated ischaemic muscles, respectively), which may explain the intensive growth of capillaries in those muscles. The findings indicate that treatment with DMOG has a potential therapeutic use in promoting angiogenesis in ischaemic diseases, and perhaps for improving muscle recovery after injury, exercise or training.

Topics: Amino Acids, Dicarboxylic; Animals; Capillaries; Disease Models, Animal; DNA-Binding Proteins; Hindlimb; Hypoxia-Inducible Factor 1; Hypoxia-Inducible Factor 1, alpha Subunit; Ischemia; Mice; Mice, Inbred C57BL; Muscle, Skeletal; Neovascularization, Physiologic; Nuclear Proteins; Transcription Factors; Vascular Endothelial Growth Factor A